The present invention relates to an improved pipe mill having special equipment to permit operation of the mill at very high speeds and more particularly to a mill having at least two cooling beds, at least two conveyors for delivering the cut lengths of pipe to both beds, and a unique selector unit having an oscillating deflector means for directing the pipe lengths alternately to both cooling beds or to only one of the beds.
In a conventional pipe mill, hot pipe is produced continuously in pipe forming apparatus which is capable of operating at speeds of 1 to 2000 feet per minute or more. The pipe, while hot, is severed, as by sawing, into commercial lengths of, for example, 20 to 40 feet as the pipe leaves the mill. A flying saw may be used to effect the cutting without stopping movement of the pipe.
The rapidly moving lengths of pipe severed by the saw are moved longitudinally on a conveyor successively onto a cooling bed where they are conveyed transversely of their axes by screw conveyors and while so moving are permitted to cool.
It is customary to provide only one cooling bed for the plant having a fast-acting rotary kickout to transfer the cut lengths of pipe from the longitudinal conveyor to the transverse screw conveyors of the cooling bed. The longitudinal conveyor is operated at a higher speed than the mill and saw so that a gap is produced between the ends of successive lengths of pipe, such gap providing time for the rotary kickout to operate.
Up to the present time the mill speed has been limited and serious problems have arisen when it has been attempted to operate at speeds of 1500 feet per minute or higher because the maximum rate of operation of the rotary kickout is limited, for example, to about 40 pipe lengths per minute. Because only one cooling bed was provided, it became necessary to shut down the entire mill when there was a malfunction or break down of the bed or associated equipment.